1. Technical Field
Various embodiments relate generally to a semiconductor device and a method for manufacturing the same, and to a semiconductor device in which a gate metal film is restrained from being oxidized and a method for manufacturing the same.
2. Related Art
A gate pattern of a non-volatile memory device among semiconductor devices is formed by patterning a conductive film for a floating gate, a dielectric film, a conductive film for a control gate, and a gate metal film.
When a tungsten silicide (Wsix) film or a cobalt silicide (Co-six) film is used as a gate metal film in a semiconductor device having a size of 50 nm or smaller, since specific resistance of the tungsten silicide (Wsix) film or a cobalt silicide (Co-six) film is high, resistance Rs of word lines is increased to degrade a program speed and a read speed. In order to solve this problem, a thickness of the gate metal film may be increased. This method, however, makes it difficult to pattern word lines and potentially causes a void to be formed within a device separation film electrically separating word lines. Thus, a method of forming a gate electrode film by using a tungsten (W) film having specific resistance lower than that of the tungsten silicide (Wsix) film and a cobalt silicide (Co-six) film has been studied.
However, a tungsten (W) film is easily oxidized during a heating process and easily corroded in a cleaning solution during a cleaning process, causing restrictions on a follow-up process.